CWE-761 詳細

CWE-761

Free of Pointer not at Start of Buffer
2009-05-27
00h00 +00:00
Incomplete
2026-10-28
00h00 +00:00
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名前: Free of Pointer not at Start of Buffer

The product calls free() on a pointer to a memory resource that was allocated on the heap, but the pointer is not at the start of the buffer.

一般情報

導入モード

Implementation : This weakness often occurs when the memory is allocated explicitly on the heap with one of the malloc() family functions and free() is called, but pointer arithmetic has caused the pointer to be in the interior or end of the buffer.

適用可能なプラットフォーム

言語

クラス: Memory-Unsafe (Often)
名前: C (Undetermined)

一般的な結果

スコープ 影響 可能性
Integrity
Availability
Confidentiality
Modify Memory, DoS: Crash, Exit, or Restart, Execute Unauthorized Code or Commands

注記:This can cause the product to crash, or in some cases, modify critical program variables or execute code.

観察された例

参考文献 説明

CVE-2019-11930

function "internally calls 'calloc' and returns a pointer at an index... inside the allocated buffer. This led to freeing invalid memory."

潜在的な緩和策

Phases : Implementation
When utilizing pointer arithmetic to traverse a buffer, use a separate variable to track progress through memory and preserve the originally allocated address for later freeing.
Phases : Implementation
When programming in C++, consider using smart pointers provided by the boost library to help correctly and consistently manage memory.
Phases : Architecture and Design
Phases : Architecture and Design
Use a language that provides abstractions for memory allocation and deallocation.

検出方法

Automated Dynamic Analysis

Use tools that are integrated during compilation to insert runtime error-checking mechanisms related to memory safety errors, such as AddressSanitizer (ASan) for C/C++ [REF-1518] or valgrind [REF-480].
有効性 : Moderate

脆弱性マッピングノート

理由 : This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
コメント : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

ノート

Currently, CWE-763 is the parent, however it may be desirable to have an intermediate parent which is not function-specific, similar to how CWE-762 is an intermediate parent between CWE-763 and CWE-590.

参考文献

REF-657

boost C++ Library Smart Pointers
https://www.boost.org/doc/libs/1_38_0/libs/smart_ptr/smart_ptr.htm

REF-480

Valgrind
https://valgrind.org/

REF-1518

AddressSanitizer
https://clang.llvm.org/docs/AddressSanitizer.html

登録情報

名前 組織 日付 リリース日 Version
CWE Content Team MITRE 2009-05-08 +00:00 2009-05-27 +00:00 1.4

変更履歴

名前 組織 日付 コメント
CWE Content Team MITRE 2010-09-27 +00:00 updated Relationships
CWE Content Team MITRE 2011-06-01 +00:00 updated Common_Consequences
CWE Content Team MITRE 2012-05-11 +00:00 updated Demonstrative_Examples, Relationships
CWE Content Team MITRE 2012-10-30 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2014-02-18 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2014-07-30 +00:00 updated Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2020-02-24 +00:00 updated Relationships
CWE Content Team MITRE 2020-12-10 +00:00 updated Relationships
CWE Content Team MITRE 2021-03-15 +00:00 updated Observed_Examples
CWE Content Team MITRE 2023-01-31 +00:00 updated Description
CWE Content Team MITRE 2023-04-27 +00:00 updated References, Relationships
CWE Content Team MITRE 2023-06-29 +00:00 updated Mapping_Notes
CWE Content Team MITRE 2025-09-09 +00:00 updated Functional_Areas, References
CWE Content Team MITRE 2025-12-11 +00:00 updated Applicable_Platforms, Detection_Factors, Potential_Mitigations, References, Weakness_Ordinalities
CWE Content Team MITRE 2026-04-30 +00:00 updated Detection_Factors
CWE Content Team MITRE 2026-10-28 +00:00 updated Common_Consequences, Demonstrative_Examples, Description, Modes_of_Introduction